I like starting gromp with vi, and getting that early blue to spam e more. If you position well, you can hit most of the mobs in each camp with the cone. That and gromp poison will make them easier to kill. And if you time it right, you can maximize your shield passive. E also resets auto attacks, so it's really nice.
The attack speed and armor shred from w is super useful for jungling. You really only need 1 point in Q, max the other two first.
I can typically do gromp, blue, wolves then red and hit level 3 at about 65% hp. It's a little sketchy for a gank, but if someone is pushed, you can catch them rather easily. Usually I prefer to get wraiths and back to get a jungle item, them gank with chilling smite or warriors.